Damn, I just noticed that there's another review request for this golang package ... long story short, I wanted to add this package to fedora too (see https://bugzilla.redhat.com/show_bug.cgi?id=1428551), but we decided to modify the existing package (golang-bitbucket-kardianos-osext) to also include the new github sources.
As of today, the rawhide and f26 builds (with updates for f25 and f24 still pending) of golang-bitbucket-kardianos-osext provide the new sources for golang(github.com/kardianos/osext) in addition to the old golang(bitbucket.org/kardianos/osext).